Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

The Centers for Medicare and Medicaid Services issued final guidance Monday that sets up a system for reimbursement. Lawmakers set aside $1 billion over four years for the program, created by Medicare legislation passed in 2003.

For hospitals in border states, the additional money can mean the difference between running a profitable business or an unprofitable one, said Don May, vice president of policy for the American Hospital Association.

“I don’t know if it will completely change their financial picture, but for those hospitals on the border, this is going to make a difference in ensuring they are there to treat the patients, not just the undocumented ones, but all the patients living in those communities,” May said.

Two-thirds of the money will be distributed to health care providers based on a state’s percentage of undocumented aliens. The remaining third will go to providers in the six states with the largest number of arrests of undocumented aliens.

The states receiving the highest amounts in the current fiscal year are California, $70.8 million; Texas, $46 million; Arizona, $45 million; and New York, $12.25 million.

Payments to providers will be made on a quarterly basis and will be adjusted proportionately if the bills exceed the state’s allocation.

One group that advocates stricter immigration policies said the government’s reimbursement of hospitals was the right thing to do.

“It seems to me that if the federal government has abdicated its responsibility for immigration enforcement, then it’s responsible for making those jurisdictions whole,” said Mark Krikorian, executive director of the Center for Immigration Studies, a think tank based in Washington.